Various cleaning articles have been created for dusting and light cleaning. For example, cloth rags and paper towels used dry or wetted with polishing and cleaning compositions have been used on relatively flat surfaces such as countertops, showers, sinks and floors. Laminiferous wipes have been proposed, as disclosed in U.S. Pat. No. 9,296,176. But, rags, wipes, and paper towels are problematic for reasons such as hygiene (the user's hands may touch chemicals, dirt or the surface during cleaning), reach (it may be difficult to insert the user's hand with the rag, wipe or paper towel into hard-to-reach places) and inconvenience (cleaning between closely-spaced articles typically requires moving the articles).
To overcome the problems associated with using rags and paper towels, various reusable dust gathering devices using felt and hair have been utilized for more than a century, as illustrated by U.S. Pat. No. 823,725 issued in 1906 to Hayden and using yarns as illustrated in U.S. Pat. No. 4,145,787. To address the problems with reusable dust gathering devices, disposable cleaning articles have been developed which have limited re-usability. These disposable cleaning articles may include synthetic fiber bundles, called tow fibers, attached to a sheet as shown in U.S. Pat. Nos. 6,241,835; 6,329,308; 6,554,937; 6,774,070; 6,813,801; 7,003,856; 7,566,671; 7,712,178; 7,779,502; 7,937,797; 8,146,197; 8,151,402; 8,161,594, 8,186,001; 8,245,349; 8,646,144; 8,528,151; 8,617,685; 8,756,746; 8,763,197; 9,113,768 and 9,198,553.
Disposable dusters having tow fibers may provide for wet cleaning as disclosed in U.S. Pat. No. 7,566,671 and in commonly assigned U.S. Pat. No. 7,803,726 and commonly assigned US 2008/0028560. But tow fibers may become matted when wet and not be suitable for cleaning a large or heavily wetted surface, such as a floor. Thus, dusters may not suitable for cleaning extremely large or heavily soiled surfaces.
Instead, sheets having fibers have been proposed, as disclosed in U.S. Pat. Nos. 6,143,393; 6,241,835; 6,319,593; 6,329,308; 6,554,937; 6,774,070; 6,830,801; 7,870,635; 8,225,453; 8,646,144; 8,617,685; 8,752,232; 8,793,832; 9,113,768 and in commonly assigned U.S. Pat. No. 8,075,977. Webs with elastic behavior have been proposed in commonly assigned U.S. Pat. No. 5,691,035. Sheets with recesses have also been proposed, as disclosed in U.S. Pat. Nos. 6,245,413; and 7,386,907. Sheets with cavities have been proposed, as disclosed in U.S. Pat. No. 6,550,092. An adhesive cleaning sheet is proposed in U.S. Pat. No. 7,291,359. Tufts are taught in commonly assigned U.S. Pat. Nos. 7,682,686, 7,838,099 and/or 8,075,977.
Yet other attempts use coatings of wax and/or oil. Coatings, such as wax and oil are generally disclosed in U.S. Pat. Nos. 6,550,092; 6,777,064; 6,797,357; 6,936,330; 6,984,615; 7,386,907; 7,560,398; 7,786,030; 8,536,074; 9,204,775; 9,339,165. Specific amphiphilic coatings are disclosed in U.S. Pat. No. 8,851,776. Swiffer® Dusters, sold by the instant assignee, have been sold with up to 7 weight percent oil for off-the-floor cleaning. U.S. Pat. No. 7,786,030 discusses various percentages of antigenicity compositions as applied to a cleaning tool. For example, U.S. Pat. No. 7,786,030 teaches using a dry lubricant having 5.0% moisture solublized in the lubricant. But U.S. Pat. No. 7,786,030 does not teach how moisture can affect tow fibers in a cleaning article or what control over moisture levels in the tow fibers is desired.
But these teachings do not address the proper amount of coatings on a cleaning article having tow fibers attached to a sheet. Too little coating is not efficacious. Too much coating is wasteful, contaminates production machinery and can leave unsightly residue. Residue is problematic as it leave the surface intended to be cleaned with a dirty appearance and can be difficult to remove.
Yet other factors should be considered. For example, the presence of water in tow fibers may lead to cohesive failure, further exacerbating the problem of depositing residue on the surface to be cleaned. But the prior art neither teaches the optimal coating weight of mineral oil to balance soil pickup performance against residue, nor the effect of moisture on the desired coating weight.
Accordingly, this invention addresses the problem of how to incorporate the proper amount of coating onto the tow fibers of a cleaning article.